Method and apparatus for measuring the specific gravity of liquid and solid mixtures



Nov. 2 1926. 1,605,171

T. M. CHANCE METHOD AND APPARATUS-Fon MEASURING THE SPECIFIC GRAVITY oF LIQUID AND 'soLID MIXTURES Filed July 26, 1924 zsheets-Sheet 2 1 Witnesses mi M Af, M

hante Nev, 2, 192s. 'A

` VUNI-'riso sT ArssrA- TEN nn'rnon vAmi Arnaiarus ron Imam 7" Anuman alec muy ze,

'l i invention yrelates to the measurement.

ofthe specific gravity of mixtures of solids and liquids such asmaintained suspensions of solids inliquids, and fluid masses such as I have described in Patents Nos. 1,224,138, issued May 1, 1917, 1,392,399, lssued October 4, 1921, and 1,462,881, iued July 24,1923.

If the lower portion of a glass" tube, held in a vertical position, be immersed 1n such fluid mass, 'the lluid mass will ll the tubel to a level coinciding with the, to of sa1d fluid mass, but the suspended sollds 1n the lluid mass within the tube immediately begin to settle and in a short time all of the said solids will fall out of the tube, the tube containing nothing but water or such solution or other liquid which may be the liquid constituent of thefluid mass. Qomcidcut with the falling of the sol1dpart1cles from the tube water enters the lower end of the tube and the tube becomes filled with Water (or other liquid.) to a higher level l of the fluid mass is directly proportional to wsa 4to a height of 5 inches, if the speci c the depth to which the tube is immersed in the fluid mass and also directly proportional to the increase in the specific gravity of such fluid mass above that ofthe Water or other liquid due to the presence of its solid constituent, and the weight of that part of the column-of Water in the tube above thel level of the fluid mass is equal to the weight of the solids in a cylindrical column of the lluifl mass such as could be contained in said tube and of a. length equal to the depth to/ which the tube is immersed in the fluid mass. For example, 'if the tube be immersed to a depth of 10 inches in an aqueous fluid mass having a lspecific gravity of 2.00 the water will lrise in the tube to a height of 10 inches, if the specific gravit be 1.50,

gravity` be 1.00 to a height of zero. ,The specific gravity vol? the luid mass is where hzheight to which liquid rises and dzdepth of immersion of the tube 1n the fluid mass.

sonnimx'rumia,v t i f e. 'rms srncmc aluvrry ,or LIQUID AND f V1924. Berlll 113.728,41.

pressurel produced by the lluid mass at Ithe depth'of immersion, It is therefore evident that suchl pressure, canbe measured in exactly the same way by a tube external to the receptacle contain ing the fluid mass, the pressure being transmitted through aconnection`made at any desired point through the walls of the con tainer, or by any form of ressure gauge by which the pressure deve oped at a certain depth of such fluid masscan be measured. If, however, the upper surface of the fluid mass is not maintained at a constant level, or if a bod of liquid of constant or variable depth be superposed upon said fluid mass as described in said Patent No.. 1,392,399, the specific gravity cannot be determined by asingle tube, or b y the pressure at a single point, except by the use of auxiliary means for determining the level of the top of the fluid mass and the depth of water superposed thereon, `and making corrections for l'these variables.

and the specific gravity I overcome these latter diiiiculties by utilzin'gthe differences in. pressure produced at two points insaid fluid mass, said points being separated by a definite vertical interval, the dill'erence in pressure at these two points being a measure of the specific grav- 1ty of the fluid mass-in this vertical interval. W'hen using this method, the total pressure caused by variations in the level of the top of said iluid mass and in the depth of said superposedwater or other liquid, will produce equal variations sin pressure at the two. points at Which the total pressures are to be measured, and the dillerence in pressure at the two points will always be directly proportional to the vertical distance between said tWo points and to the Weight of the suspended solids in this vertical interval, and this difference in pressure lcan therefore be used to determine thespecific gravity by the formulae h-h d where L-fheight or pressure recorded for the point of greatest immersion or lower point, hzthat at least immersion or higher` point, dzdepth of immersion at the `lower point and Z= depth of immersion at the hi her point in said fluid mass. f

any dillerent types ,of apparatus for the measurement of this gdifl'erencein thepres-v specific gravity= 1 suresdeveloped at the two fixed points, may be designed by those skilled in the art of measuring pressures.- I therefore intend the drawings to illustrate diagrammatically variations in types of apparatus such as may be used in carryin outnny invention.

rlhe foregoing description of the principles upon which my invention is based is illustrated by the diagrams Figs. I and II which are vertical cross-sections of a container holding a iiuid mass of the described type with a bod of liquid superposed upon the fiuid mass, t 1e depth of fluid mass bein variable and the depth of the superpose liquid also being variable, the drawin s illustrating the measurement of the speci c gravity by the difference in pressure at two oints in said iiuid mass separated by a iXe vertical interval. rlhe drawings do' not show the means by which the fluid mass is agitated as that is fully described in the said patents.

Fig. III is a vertical cross-section showing a specific gravity indicator applied to a Hui mass of the described type composed'of sand and water, in which agitation is effected mainly by slowly rising water introduced near the base of the appara-tus, the drawing showing a part of an a aratus such as is used in washing anthracite coal at several places in the State of Pennsylvania, together with a specific gravity indicator having the pressure. measuring tubes inside thecoal separating receptacle; while the indicators and gauges are outside the receptacle. The drawing shows means for directly measuring the difference in height of the water in two gauge glasses by a movable scale and also shows an automatic visual specific gravity indicator using a dial and moving Vhand or pointer to continuously show the'speciic gravity. Y

Fig. IV is a vertical cross-section and elevation of a specific ravity indicator `applied tothe same type 0% apparatus as described for Fig. III in which the pressures at the.

two fixed depths are transmitted, V.by airrljf under compression equal to the said two pressures, to an indicator, recording apparatus and annunciator system. Y

` Fig. IVL is an enlarged verticalcross-section and Fi IVb a bottom 'view' ofthe lower parto the tubes shown by Fig'IV.

Fig.4 V illustrates the use lofiiexiblediaphragms attached'to means for measuring. the diierence in the pressures exerted uponthem. i In Figs. I and II the tank lis partly filled with' an agitated fluid massv '2.0i the: def-f scribed type, with a superposed body`V oiliq. uid 3,V the-top of theuid mass beingI desiglnated by the line A-A and `thetop of the liquid by the line B-.B. Y TheA fluid mass used'for this illustration isassumed to have a' specific gravity of 2.00 and the liquid (water) to have a specific gravity of'LOO,

5 measures the increase in the specific gravity over that of water in both cases. In the drawings the distance D is the di`erence in depth of immersion of the two tubes t' and 5 and Il is the di`erence in the height to which water rises in the two tubes; d is the total depth of immersion of the longer tube, al the depth of immersion of the shorter tube, h the height to which li uid (water) rises in the longer tube and i1. the height to which it rises in the shorter tube. Hence sp. gr.=l +-g7=l+- If. the tubes 4 and 5 were both immersed in the fluid mass to the same depth below the water line B--B, water would rise to the same height in both tubes; if then one of the tubes be lowered to greater depth the additional height to which water rises in that tube will measure the increased hydrostatic pressure at the base of the lower tube, and this increased pressure will measure the increase in density due to the resence of the solid constituent of the ilui mass. It the depth of the superposed bod, of liquid (iwa-ter) be known, calling this epth W, the specific gravity can be calculated thus: l

d-i-L-W Sp. gr.: 9

er gr-:nw-f

water and the speciic gravity of the fluid vmass is assumed to be 1.70. Two tubes 4 and 5 immersed to different depths in 2, are provided with clean-out rods shown by dotted lines and having enlarged heads 6 and 7, the rods extending to the ,bottom of the tubes. These rods have an enlargement at their lower ends so that there is but a small clearance between the rod and the inside of the ytube in order to prevent the entrance of coarse material into the tubes. These rods are (preferably madev so that they can be rotate in order. that there may be unobstructed passage :tor water at all times between the.rods and the inside of the tube.

The construction of and a means for rotating such clean-out rods is illustrated in Figs. IV,

V,T he quantity of water su IVn and IV". Pressure developed in tubes 4 and 5 is transmitted through connections 8 and 9 to two vertical pipes 10 and ll'in which water therefore can rise to a height dependent upon the pressures developed in 4 and 5. These pipes 10 and 11 are" closed at the bottom but are provided with clean out cocks 12. Thepipes 10 and 11 are equipped with gauge glasses 13 and 14 open' 'at thel top, mounted upon and in communication with 10 and 11 through gauge glass fittings as shown by the drawing. The water in 10 and 11 is therefore free to rise in these gauge glasses 13 and 14 toa height equal to 'its height in 10 and 11. A specific gravity scale 15 is sli'dably mounted on gauge glass 14, on the gauge glass guard rods, or in other suitable manner, so that it can be moved vertically to bring the 1.00 specific gravity mark level with the water in 14, the scale then showing the specific gravity by the graduation which is llevel with the water in gauge glass 13. It is found advantageous to have a continuous flow of clean water flowing from pipes 10 and 11 through 8 and 9 into 4 and 5, so that a -slowly moving current of water is continuously flowing out of the lower ends of tubes 4 and 5, .decreasing the tendency ,ofl sand to find its way up into these tubes, and facilitating the dropping out of any sand that may enter. Periodic or continuous rotation of the clean-out rods in these tubes also facilitates the removal of sand and other foreign matter. To provide clean water for this purpose a valved water supply pipe is shown by 17 provided with outlet nozzles which feed an equal quantity of water into each of the pipes 10 and 11. plied io these pipes is preferably small, epending upon the size of the apparatus, say one quart more or less per minute. For complete iushing and cleaning out of the apparatus a larger supply should be availabl The apparatus as above described is complete in itself, but the .drawing is used to illustrate an automatic visual indicatorof the dial type, whichmay readily be added to the apparatus as already described by inserting a float 18 in each pipe 10 and 11, these floats being suspended by a. flexible cord, wire or chain 19 by means of pulleys 20 mounted on a counter-weighted frame 21 which i's suspended on pulley 22 by flexible cord, wire or chain 23 to which lcounter weight 24 is attached. From pulleys 20 the cord 19 is passed one and a -half turns around grooved pulley25. j

The pulleys 22 and 25 are mounted upon fixed supports as shown by 26, 27 and 28, therefore if floats 18, 18 both rise or fall together, the movement is adjusted by rising or falling of the counter-weighted frame pulley 21, pulley not being affected'by equal movement of the two floats 18, 18. If,

to each other,

l from the bottom of tubes 40 and 41 however, the two floats 18, 18 move relatively oneri'sing or falling morefthan the other, then this difference in movement Nwill produce rotation of the pulley 25 moving a hand or pointer 30 attached to the i shaft on which pulley 25 is mounted, the movementof the pointer showing by. the

graduations of the dial 29 the specific gravity of the Huid mass.,

Rotation of the-pulley 25, or movement of l the ycord 19, may be used to actuate the` marking arm of registering yrecorders of types illustrated by Fig. IV and in common use, and` thus a continuous and ermanent record of variations in the specific gravity of the fluid mass can be obtained. The dial 29 may be equipped with electric Contact points set at any desired specific gravity graduations as illustrated in Fig. IIV 'so that the pointer 30 in assing over these points will complete an e ectric circuit and operate gongs or other forms of annunciators or alarms asalso illustrated by Fig. IV.

In the drawing the indicator dial 29 and the fixed pulley 22 carrying the counterweighted pulley frame 2l are mounted upon and vertically above the pipes 10 and 11, but these structures are not necessarily mounted in this position. A

In Fig. IV, the tank 1, agitatediuid mass 2, and superposed water 3 and the composition and specific gravity of the fluid mass, and the depths of immersion of the tubes are as in Fig. III, the tubes in this case, 40 and 41 are closed at the top and are continuously supplied with compressed air through pipes 42, 43 which through the cylinder 44, pipesl 40 and 41 is regulated by needle valves 49- and 50, .these valves being so constructed that a small but continuous flow of air issues through a port in said valves that lremains permanently open, the supply to each being regu` lated by the bubbles of air coming to the surface of the water at each tube. By this meansl the pressure on each side of the piston 51 is at all times vequal to the pressures developed by immerslon.

The piston rod 52 has an vextension rod or cord -53 attached to a spring'54' and carrying an indicator pointer 55 with marking pen or pencil in operative relation to the revolving cylinder recorder 56, and also ,carries a contactor arm 57 sliding on the contact strip 58 adapted to make contact with movable contact points, 594 and, 60= and thus actuate the fluid mass at the depths of as referred to in the description of Fig. III,

the means shown comprising a gear 63 driving gears/64, 65 by which rods 66, 67 are slowly rotated, the gear 63 beine driven through bevel gears 68, 69 by pulley t70 which is driven by'any suitable source of power. The rods 66, 67 are carried down through l pipes. The described construction permitsl tubes 40, 41 in pipes 71, 72 open to the at-v mosphere at the top, and extending down to or slightly below the bottom of tubes 40, 41, so that fluid mass and water may enter and rise in these pipes, while its entrance into tubes 40, 41 is prevented by the presence of the compressed air. annular plugs which extendingup into tubes 40, 41 and being rotated b t and the enlargement at the lower end of rods 66, '67 are illustrated by Fig. IVn and IV", the rods 66, 67 having an enlargement 7 3 leaving small clearance between it and the inside of pipes 71, 72; Aattached to this enlargement 7 3 is an open grid 74 carrying the annular tube cleaner between which.y and the inner wall of tubes 40, 41.and the outer Vwall of pipes 71, 72 there is but a small clearance. Rotation of the rods 66, 67 therefore produces rotation of tube cleaner 75 and thus prevents clogging and facilitates the dis-` charge of materials that may have "found from the bottom of tubes 40, 41. The open grid support or connection 74 also contributes to this end and also vpermits'the pipes 71, 72 to fill with water and lto discharge sand'or other solid matter from'said the apparatus to be built with the tubes 40, 41 absolutely air tight which would be difficult if the clean-out rods were takenI through the top of'these tubes through pack#k ing glands or any form of stuiiing box. The ipes 71, 72 are shown Vprojectmg slightly elow the bottom of tubes 40, 41.

Fig. V illustrates a construction in which the dierence in pressures is directly measured and transmitted by iexible diaphragms at the base of the tubes 4, 5 which are both equipied with a flexible diaphragm 75 attache to a rod 76 operatively connected to av knife-edge 77 which is in contact wlth the Alever 78 free to oscillate on knife-edge 79,.

the difference in pressure developedat'the base of the tubes 4 and '5 reacting uponthe spring 80, adjustable by screw 81, whereby themovements of the pointer 82 attached to lever 78, are proportional to said differences in pressure. The .pointer arm 82 may of course be made to actuate the contacts vof The rods 66, 67. carry e rods 66, 67 yprevent clogging of the tu es. These plugs electric circuits connecting with control and annunciator system as already described.

The drawings are diagrammatic and thel several parts are intended to represent equivalent devices performing like functions or producing like results. Many 'of the parts shown are exaggerated in order to vshow details plainly and for the same reason the necessary supports for the several elements are not shown.

Ido not limit the application. of my invention to the exact details or forms of construction and arrangement shown by the drawings and as herein described, as it is obvious that apparatus of many other kinds may be used without departing from the essential features of my invention as defined in the appended claims.

Having described my invention I claim, 1.A method forV measuring the specific gravity of fluid masses whichare maingreater/than that ofthe liqui and consists -in -iInmersin two Y ressure a es stantially insoluble therein,- which i in' said luid mass, one of said gauges.4 being immersed to agknown greater vertical oeptn v in said fluidmass than the other, in measuring the dierence inpressure per unit of area at, the two depths of immersion, yand in dividing said difference by the weight er unit of area of aV columnof said liquid ree from suspended Vsolids vand equal in'height l s to said known verticaldiference in depth. their way into 4these tubes and also insures lthe free and unobstructed discharge of a1r` pressure gauges in said' fluid mass, one of said gauges being immersed to a known reater vertical depth in said fluid mass t an the other, in measuring 'theA difference in pressure per unit of area at `the two depths of immersion, in which the two pressure i gauges register the pressures by the height o f columns of liquidand the specific gravity is determinedv by dividing the difference in vheight betweensaid columns bysaid known vertical difference' in depth and adding 1.00 to the result.

3'. Apparatus for measuring the specific gravity of fluid masses which are maintained suspensions of comminuted solid matter in liquid, said solids havingspecific gravities greater-than that of the liquid and being *substantiallyv insoluble therein comprisin in combination two pressure'gauges adapte tobeso immersed in such maintained suspensionthat one of said gauges will be immersed .to a known greater vertical depth in said fluid mass than the other and means for" measuring the diii'erences in the pre-s- 6. The apparatus of claim Skin which sures indicated by said gauges. y Heats are placed in said manometer tubes, 4. The 'apparatus of claim 3 in which said ioats 'being operatively connected t0 the pressure gauges are manometer tubes. an indicator whereby differential movements 5 5. The apparatus of claim 4 in which the of the two oats with-reference to each other 415 means for measuring diierences in presare indicated. 1 sure is a movable graduated scale whereby Signed at Philadelphia, Pennsylvania, the specific gravityV of the saidjmaintained this 24th day of July, 1924.

suspension is directly measured by said i 10 scale. .v f THOMAS CHANCE. 

